Fastener attaching apparatus

ABSTRACT

FASTENER APPLYING APPARATUS HAS MEANS FOR FEEDING A STRIP OF END-TO-END CONNECTED FASTENERS ALONG A PREDETERMINED PATH TOWARDS A POST LIKE PROJECTION WHICH THE FASTENER IS TO BE APPLIED. UPON ACTUATION, THE LEADING FASTNER OF THE STRIP IS SEVERED FROM THE STRIP AND A CONNECTING TAB OR NECK, WHICH CONNECTS THE LEADING FASTNER TO THE NEXT ADJACENT FASTENER, IS BENT LATERALLY. WHEN THE LEADING FASTNER IS APPLIED TO THE POST, THE LATERALLY EXTENDING NECK FUNCTIONS TO HOLD A PLATE-LIKE MEMBER AGAINST THE PANEL FROM WHICH THE POSTS EXTENDS.

Oct. 5, 1971 R. c. BREHM ETAL 3,609,832

FASTENER ATTACHING APPARATUS Filed July 22, 1969 7 Sheets-Sheet l Oct. 5, 1971 c, BREHM EIAL 3,609,832

FASTENEH ATTACHING APPARATUS '7 Sheets-Sheet 2 Filed July 22, 1969 Oct. 5, 1911 Q BREHM ETAL FASTENER ATTACHING APPARATUS 7 Sheets-Sheet Filed July 22, 1969 Oct. 5, 1971 c, BREHM ETAL 3,609,832

FASTENER ATTACHING APPARATUS Filed July 22, 1969 7 Sheets-Sheet s O N 83% c0 m E 80 $3 Q0 IIO Oct. 5, 1971 R. c. BREHM ETAL 3,609,832

FASTENER ATTACHING APPARATUS Filed July 22, 1969 7 Sheets-Sheet 6 Oct. 5, 1911 c, BREHM El'AL 3,609,832

FASTENER ATTACHING APPARATUS '7 Sheets-Sheet '7 Filed July 22, 1969 3,609,832 FASTENER ATTACHIN G APPARATUS Ronald Carl Brehm, Carlisle, Robert Graham Lundergan, Camp Hill, and William Roderick Over, Harrisburg, Pa., assignors to AMP Incorporated, Harrisburg, Pa.

Filed July 22, 1969, Ser. No. 843,540 Int. Cl. 323p 19/08 US. Cl. 29-212 R 6 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to mechanical fasteners and to apparatus for applying mechanical fasteners, the fastener being partially formed at the time of application. The invention is herein disclosed in an embodiment adapted to apply a fastener to an electronic chassis having an upstanding post or tab for the purpose of holding a small panel against the surface of the chassis during assembly although it will be apparent that the invention can be used under other circumstances.

In accordance with one assembly procedure for electronic devices, a plurality of insulating plates having contact terminals thereon are temporarily secured by a fastener to the surface of the chassis on the assembly line. After the wiring operations and other assembly operations have been completed, the conductors extending to the terminals are dip-soldered. At the time of soldering it is desirable to solder the fastener to the chassis to permanently secure the insulating panel in position. This method is used for products which are manufactured in large numbers such as chassis for television sets and under other circumstances where costs must be maintained at a minimum level. The fasteners employed must firmly secure the panels in position while the chassis is being moved along the assembly line and must be amenable to a subsequent soldering operation to secure the fastener permanently to the chassis.

An object of the present invention is to provide an improved applicator for applying fasteners to upstanding posts on electronic chassis or the like. A further object is to provide a fastener applying device having means therein for partially forming a fastener during the applying operation. A still further object is to provide a fastener in end-to-end strip form. A still further object is to provide an improved method of applying fasteners to upstanding posts or the like.

These and other objects of the invention are achieved in a preferred embodiment thereof which is described briefly in the foregoing abstract, which is described in detail in the description presented below, and is shown in the accompanying drawings in which:

FIG. 1 is a pictorial view illustrating the manner in which a tool in accordance with the invention may be used on a production line.

FIG. 2 is a perspective view illustrating the manner in which fasteners in accordance with the invention are employed to hold an insulating panel against a chassis panel.

United States Patent FIG. 3 is a perspective view of a short section of fasteners in strip form.

FIG. 3A is a sectional side view of a fastener in accordance with the invention.

FIG. 4 is a perspective exploded view of a mechanism (excluding the air cylinder) of an apparatus in accordance with the invention.

FIG. 5 is a sectional side view of the mechanisms of the apparatus in accordance with the invention showing the positions of the parts at the beginning of an operating cycle.

FIGS. 6, 7, and 8 are views similar to FIG. 5 but showing the position of the parts at successive stages of the operating cycle.

FIG. 9 is a top view of the portions of the apparatus shown in FIG. 5.

FIGS. 10, 11 and 12 are sectional side views of the nose portion of the apparatus illustrating the application of the fastener to an upstanding post on a chassis.

FIG. 13 is a view taken along the lines 13-13 of FIG. 11.

Referring first to FIG. 1, a fastener applying tool in accordance with the invention is intended to be suspended above an assembly line or work bench 5 by means of a suitable cable so that the operator may grasp the tool and apply fasteners to work pieces when needed. Fasteners 4 in accordance with the invention are manufactured in continuous strip form, the strip comprising a continuous web 13 having pairs of sidewalls 14 at spaced apart locations along its length. The sidewalls are curved inwardly towards each other and towards the undersides of the web so that they are adapted to be telescoped onto an upstanding tab or post 6 on a panel 8. The edges of the sidewalls are advantageously provided with spurs or serrations which dig into the post at the time of application and help to retain the fastener on the post. The adjacent fasteners of the strip are connected by connecting sections 18 of the Web and the leading fastener of the strip has a laterally extending foot portion 20 which is formed by the applying tool. The web is also provided with openings 19 between adjacent terminals which facilitate the severance of the leading fastener from the strip at the time of application.

Fasteners in accordance with the invention are advantageously formed of a material having a relatively high yield strength and having relatively good ductility. Good ductility is required because of the fact that the connecting neck portions are drastically deformed at the time of application and the fasteners must be capable of withstanding this deformation. Fasteners in accordance with the invention must also be relatively strong in order to provide the required amount of holding power. It has been found that a standard stainless steel, AISI 302 in onefourth hard temper is well suited to the manufacture of fasteners in accordance with the invention although equivalent materials can be used if desired.

In FIG. 2, fasteners 4 have been applied to upstanding tabs or posts 6 of a panel 8 of an electronic chassis or the like. The fasteners serve to hold insulating boards 10 on the surface of the panel 8 during the assembly process, the panels or boards 10 having a plurality of male terminal members 12 thereon. As shown clearly in FIG. 2, the fasteners 4 applied to the tabs 6 are positioned such that the laterally extending foot portions 20 extend over the surface of the insulating panel 10 to hold this panel in position. After the chassis has been wired by connecting wires to the interiors of the terminals 12, the entire assembly is dip-soldered so that the wires are soldered to the terminals and at the same time, the fasteners 4 are soldered to the tabs or posts 6.

The disclosed form of fastener applying tool 2 comprises a conventional piston cylinder 2-4 which is supplied by compressed air by an air line 26, the operation of the tool being controlled by a trigger valve 28 to drive a piston rod 30 rightwardly from the position shown in FIG. 5 to the position shown in FIG. 7. The piston rod then returns to its initial position, either under the influence of an internal spring or, in the case of a double acting cylinder, under the influence of compressed air.

During application of a fastener to an upstanding tab or post 6, the leading fastener of a strip of fasteners is severed from the strip by means of a severing bar 32 which moves between the leading fastener and the next adjacent fastener (see FIG. 6) and bends the connecting section 18 between these two fasteners laterally so that the next adjacent fastener is now provided with a laterally extending foot 20, the laterally extending foot on the leading fastener of the strip having been formed during the preceding cycle. The leading fastener is then advanced through a nose piece 94 of the tool and pushed onto the tab by means of a pair of pusher arms 34. When the fastener comes to rest on the foot the laterally extending foot portion 20 projects over the surface of the insulating board to retain it on the panel. The fastener strip is fed during the final portion of the operating cycle by means of a feed pawl 36 which is first retracted, see FIGS. 5 and 6, and then advanced as shown in FIGS. 7 and 8. The various mechanisms and linkages by means of which these severing, inserting and strip-feeding operations are carried out will now be described in detail.

The fastener strip is fed from a reel (not specifically shown) through a guide tube 42 which is supported in a mounting block 44 between a pair of spaced-apart sideplates 38, 40. The right-hand end of the tube is received within a recess in the end of an elongated frame block 50 which is mounted between the sideplates 38, 40 by fasteners 60, 62. The frame block 50 extends obliquely downwardly from its left-hand end, as viewed in FIG. 5, thence horizontally as shown at 54 towards the nose of the tool so that the fastener strip is guided along a path towards a nose piece 96 at the front of the tool. Spacedapart depending flanges 56 are provided on the left-hand portion 52 of the frame block and similar flanges 58 are provided at the right-hand end of the frame block, these flanges defining the guide path for the strip. It should also be mentioned that the fastener strip is supported against the underside of the frame block by an insertion slide 140 which extends beneath the portion 54 of the frame block and which will be described in greater detail below.

The feed pawl 36, which advances the fastener strip during each operating cycle, comprises a pair of spacedapart arms 64 which are pivotally mounted at their rearward ends as viewed in FIG. 5, on a pin 66 and a depending feed arm 70 which extends through an opening in frame section 54. A torsion spring 68 surrounds this pin and bears against the feed pawl to bias it in clockwise direction as viewed in FIG. 5 and against the fastener strip. The lower end of feed arm 70' is notched as shown at 71, the width of this notch being substantially equal to the Width of the connecting sections 18 of the strip so that these connecting sections are straddled by the feed arm.

The pin 66 on which feed pawl arms 64 are mounted extends through openings 73 in the parallel plate sections 74 of a lever 72, these plate sections being connected by a bight section 75. The ends of the pin extend beyond plate sections 74 and through slots 77 in side plates 38, 40 to guide the pin, and the feed pawl, along a rectilinear path of reciprocation. Lever 72 comprises one element of a toggle mechanism, the other element comprising a lever 80 which is pivoted to the lower ends of plate sections 74 by a pin 78. A cam roller 76 is mounted on the pin 78 and disposed in a recess in lever 80, this cam roller being engageable with a cam surface generally indicated at 86 in a manner described below. The left-hand end of 4 lever 80 is fixedly mounted at 82 on a pin which extends through an opening in the end of this lever, through slots 144 in the insertion slide 140, and has its ends fixed in the side plates 38, 40.

The camrning surface 86, against which roller 76 bears, is provided on the central section 88 of a camming block 90 which is fixed to the end of the piston rod 30. The surface 86 has a flat section 86a on its right-hand end as viewed in FIG. 5 which merges with an inclined section 86b so that when the carnming block 90 moves rightwardly from the position of FIG. 5 to the position of FIG. 6, toggle lever 80 is permitted to swing through a clockwise are thereby drawing the toggle lever 72 leftwardly. This movement of toggle levers 72, 80 is brought about by a spring 84 secured to the web portion 75 of the toggle lever 72 at one end and to a suitable mounting pin extending between the sideplates 38, 40 at its other end. When the toggle is broken in the manner shown in FIGS. 5 and 6 the feed pawl 36 is retracted by an amount such that the depending feed arm 70 rides over the fastener strip and lodges between the fourth and fifth fasteners of the strip as viewed in FIGS. 5 and 6. When the camming block 90 returns to its initial position, upon retraction of the piston rod (FIGS. 7 and 8), the toggle mechanism is partially straightened so that the feed pawl is advanced by an amount substantially equal to the length of one of the fasteners thereby to feed the strip. This strip feeding operation takes place after the leading fastener of the strip has been severed and pushed onto a tab and the connecting section 18 between the leading fastener of the strip and the next adjacent fastener has been bent laterally. The severing and bending operations are described immediately below.

At the beginning of the operating cycle, the leading fastener of the strip will be supported on the fiat platform surface 98 of the nose piece 94 and beneath the forward end 96 of the frame block 50. Nose piece 94 is provided with upstanding sidewalls 100 which are relieved at 194 for the accommodation of the insertion arms 34. The platform portion 98 of this nose piece has a centrally located upstanding boss 102 which functions to locate the nose piece of the tool with respect to the post or tab at the time of application. The previously identified severing and bending bar 32 has a pointed upper end so that when it moves upwardly from the position of FIG. 5 to the position of FIG. 6, it will enter the opening between the leading fastener and the next adjacent fastener, sever the leading fastener from the strip and bend the connecting section 18 between the two fasteners against the surface of a bending block 108. This bending block is held by a screw against the underside of the leading portion 96 of the frame block. In order to permit the bending bar 32 to move through the insertion slide 140, a suitable opening 106 is provided in the web of the slide at its right-hand end as shown in FIGS. 4 and 6.

The severing and bending member 32 is integral with, and extends from, a block 92 which is mounted by means of a screw in a pocket of a mounting block 112 This mounting block extends between, and is secured at its ends, as by welding, to a pair of spaced-apart parallel arms 114 which are disposed substantially against the inner surfaces of the side plates 38, 40. Arms 114 extend leftwardly, as viewed in FIG. 5, on each side of, and straddle, the camming block 90. The left-hand portions of these arms extend upwardly to a fixed pin on which they are pivotally mounted, a cylindrical spacer 118 being provided on the pin between the arms to hold them in spaced-apart relationship at their left-hand ends. It will thus be apparent that when the arms 114 and the mounting block 112 are swung upwardly from the position of FIG. 5 to the position of FIG. 6, the severing and bending member 32 will move between the leading fastener and the next adjacent fastener to carry out the severing and bending operations discussed above.

The upward movement of the arms 114 is accomplished by rollers 122 which are mounted on a pin 124 which extends through elongated slots 126 in the sides of the plates 38, and through an opening 125 in the camming block 90. One end of this pin may have an enlarged head as shown and in FIG. 4 the other end may be provided with a suitable cotter pin. One roller 122 is provided on each side of the camming block 90, these rollers being adapted to bear against the lower edges 128 of the arms 114. The lower edges 128 of the arms 114 are contoured such that the desired upward movement of the lever arms 114 will be achieved during rightward movement of the camming block 90.

The lever 116 is lowered, when the piston rod 30 is retracted, prior to feeding of the fastner strip by means of a camming pin 130 which extends laterally through the central section 88 of the camming block 90 and has ends disposed between opposed surfaces of the arm 114. The ends of pin 130 engage camming edge portions 134 of relatively thin cam plates 132 secured to the opposed surfaces of the arms 114. As is apparent from FIGS. 5-7, the ends of this pin will move over and above the camming plates 132 during the forward stroke of the camming block 90 but will move against the downwardly inclined edges 134 of these thin camming plates during the return stroke of the piston rod and the camming plate 90. If desired, an auxiliary spring may be provided on the arms 114 to return them to their starting position (FIG. 5) after the pin 130 has moved leftwardly of the plates 132. However, it has been found that this spring is not ordinarily necessary since the arms 114 will return to its starting position under the influence of their own momentum.

Application of the leading fastener of the strip to the tab or post, after this fastener has been servered from the strip, is accomplished by rightward movement of the inwardly directed ends 34 of a pair of spring arms 136 which extend from the opposite sides of a channel-shaped saddle member 138. At the beginning of the cycle, the ends 34 of the arms 136 will be lodged between the leading fastener of the strip and the next adjacent fastener and will push against the sidewalls of the leading fastener during rightward movement of the saddle and the previously identified insertion slide 140-. The saddle 138 has a snap fit on the underside of the right-hand end of the channel-shaped insertion slide 140 which extends beneath the portion 54 of the frame block so that its right-hand end is supported on the platform section 98 of the nose piece 94. The left-hand end of this insertion side has enlarged sidewalls 142 in which elongated slots 144 are provided. The previously identified pin 82, upon which the toggle lever is mounted extends through these slots and the ends of the sidewalls of the insertion slide straddle the ends of this toggle link. The insertion slide is thus permitted to move rightwardly and leftwardly by an amount equal to the length of the slots 144.

Reciprocation of the insertion slide is affected when the upper end of a pusher bar 148 which is secured to the face of the camming block and is disposed between the opposed surfaces of the arms 114. The insertion slide has 21 depending boss 145 on its underside adjacent to its forward end. This boss defines a rearwardly facing shoulder 146 which is engaged by the pusher bar during forward movement of block 90 thereby to advance the slide. It will be apparent from the position of boss 145 that insertion of the leading fastener takes place towards the very end of the forward stroke of the camming block and after the leading fastener has been severed from the strip. Since the severing member 32 is between the insertion arms 136, it does not interfere with the insertion operation. Return of the insertion slide to its initial position is accomplished by a second boss 150 on the underside of the insertion slide adjacent to its left-hand end which has a forwardly facing shoulder 152 which is also engaged by the upper end of the bar 148. The return stroke of this insertion slide takes place towards the end of the return stroke of the piston rod. During the return of this insertion slide, spring arms 136 are biased outwardly and move over the surface of the leading terminal of the strip until they lodge between the leading terminal and the next adjacent terminal. It will be noted that the opposed sides of the sidewalls 100 of nose piece Q4 are relieved as shown at 104 to permit such outward movement of the spring arms.

In use, the parts will normally be in positions of FIGS. 5 and 10. When the operator wishes to apply a fastener to an upstanding post or tab, he first lowers the tool until the end of the nose piece is disposed against the surface of the panel and the tab, as shown in FIG. 13, extends partially into the leading fastener of the strip. The tool is thus centered with respect to the tab by the leading fastener of the strip. The operator then merely presses the trigger mechanism to admit compressed air into the cylinder causing rightward then leftward movement of the piston rod and the camming block 90. During rightward movement of the camming block 90, severing member 32 first moves upwardly to sever the leading fastener from the strip and to bend the connecting section 18 between the leading fastener and the next adjacent fastener upwardly. The severing member dwells in this raised posi tion for a short time while the pusher bar 148 moves against the shoulder 146 of boss 145 to move the insertion slide rightwardly from the position of FIG. 6 to the position of FIG. 7. After such rightward movement of the insertion slide, the fastener will be fully pushed onto the tab with the foot portion of the fastener bearing against the surface of the panel being secured in position. The piston rod then returns to its starting position and the lever 11-6 is lowered under the influence of the pin and the thin camming plates 132. After the severing member has been lowered, the strip is fed a distance equal to the length of one of the fastening members by the action of the camming surface 86 which partially straightens the toggle mechanism comprising the toggle arms 72, 80. It should be noted that a suitable stop pawl 160, which may be identical to the feed pawl is provided and is mounted on a pin 164 leftwardly of the feed pawl. Stop pawl has spaced-apart rearwardly extending arms through which the pin 164 extends and a depending arm 168 which bears against the strip and lodges between adjacent connecting devices thereof. A torsion spring is mounted on the pin 164 and biases the pawl 1 60 in a clockwise direction as viewed in FIG. 5. This stop pawl permits the strip to be moved rightwardly as viewed in FIG. 5 but prevents the strip from being pulled leftwardly while the feed pawl is being retracted.

A salient advantage of a fastener applying method and apparatus in accordance with the instant invention is that the fasteners can be provided in a convenient end to end strip form although they are reformed during application to provide laterally extending portions which perform a substantial and important holding function. It will also be apparent that centering of the tool on the work piece, that is on the tab to which the fastener is applied, is a relatively simple operation which can be carried out readily by an unskilled or semi-skilled operator. Finally, the entire sequence of operations can be carried out in an extremely short time so that fasteners can be applied to work pieces such as electronic chassis moving past on a production line, as fast as the operator can locate the tool on the tabs to which the fasteners are being applied.

While the fasteners are soldered to the post in the disclosed embodiment, the soldering step can be eliminated if desired and the fastener can function by virtue of its frictional engagement with the post. Furthermore, it is within the scope of the invention to provide alternative forms of fasteners and posts, the design of which would be dictated by the requirements of a particular set of circumstances. A salient feature of a fastener in accordance with the invention is the laterally bendable section 18 of the fastener strip. By virtue of the fact that this section is formed laterally at the time of application, the fasteners can be supplied in the form of a continuous strip, an arrangement which is vastly more convenient than the use of loose piece fastening devices. Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only.

We claim: 1. Apparatus for applying fastener members to posts or the like, said fastener members being in end-to-end strip form, adjacent fasteners of said strip being connected to each other by neck portions, said neck portions extending substantially parallel to the axis of said strip and being adapted to be bent laterally to form holding means, said apparatus comprising:

first feeding means for feeding a strip of said fasteners along a predetermined path through said apparatus,

severing and bending means for severing the leading fastener of said strip from the next adjacent fastener of said strip and for bending the connecting neck portion of said leading fastener laterally of said strip, said severing and bending means comprising a bending and severing arm movable laterally of said path and between said leading fastener and said next adjacent fastener of said strip, said arm being effective to bend the connecting neck between said leading fastener and said next adjacent fastener at the time of severance, and

second feeding means for feeding the leading fastener of strip from said apparatus and onto said post.

2. Apparatus as set forth in claim 1 wherein said second feeding means comprises pushing means between the leading fastener of said strip and the next adjacent fastener, said pushing means being effective to push said leading fastener onto said post.

3. Apparatus for applying fastener members to posts or the like, said fastener members being in end-to-end strip form and comprising body portions and connecting neck portions extending between the body portions of adjacent fasteners, said neck portions being adapted to be bent laterally of said body portions and function as a holding means after application of one of said fasteners to a post, said apparatus comprising:

first feeding means for feeding a strip of said fasteners along a predetermined path through said apparatus,

severing and bending means movable laterally of said path between the leading fastener of said strip and the next adjacent fastener of said strip to sever said next adjacent fastener at the rearward end of said leading fastener and to bend the said connecting neck portion between said leading fastener and said next adjacent fastener laterally of said next adjacent fastener,

second feeding means for feeding said leading fastener independently of said strip thereby to move said leading fastener onto one of said posts.

4. Apparatus as set forth in claim 3 wherein said second feeding means comprises a reciprocable feed slide having arm means thereon extending between said leading fastener and said next adjacent fastener, said arm means being effective to push said leading fastener onto said post upon movement of said feed slide in one direction.

5. Apparatus as set forth in claim 4 wherein said first feeding means comprises a feed pawl and toggle means for reciprocating said feed pawl.

6. Apparatus as set forth in claim 5 including a reciprocable actuating rod having means thereon for engaging said feed slide to reciprocate said slide and having camming means thereon engageable with said toggle means to reciprocate said feed pawl.

References Cited UNITED STATES PATENTS GRANVILLE Y. CUSTER, .lR., Primary Examiner 

